Fabric handling



1965 R. R. WALTON ETAL 3,168,307

FABRIC HANDLING 2 Sheets-Sheet 1 Filed July 9, 1962 R. R. WALTON ETAL 3,168,307

FABRIC HANDLING Feb. 2, 1965 2 Sheets-Sheet 2 Filed July 9, 1962 Ll ?T- #7 O O O O rid United States Patent M 3,168,307 FABRIC HANDLING Richard R. Walton, 19 W. Hill Place, Boston, Mass, and

George E. Munchbach, Roslindale, Masag said Munchbach assignor to said Walton, Boston, Mass.

Fiied Juiy 9, B62, Ser. No. 208,282 11 Claims. (Cl. 27126) This invention relates to fabrics and in particular to separating a top piece of fabric from a stack without disturbing the stack.

In the garment and laundry industries, stacks of fabric pieces are often produced, as when cutting from a pattern or when ironing, and then the pieces are removed one at a time for a further operation, such as sewing or folding. Heretofore, it has been necessary to separate the pieces by hand, which has prevented automating these industries.

The character of fabrics put them in a special category in regard to automatic handling. Their limpness and softness cause contacting surfaces to intermesh making it difficult even by hand to differentiate between adjacent pieces; their limpness makes lifting difiicult; their roughness causes the top piece to disrupt the stack when dragged over it; threads at the edges of adjacent pieces are often entangled; the edges of adjacent pieces are often not aligned.

Vacuum and air devices have been considered for separating such pieces, but with little success. Vacuum is unreliable because two or more pieces may rise when a sub-atmospheric condition is produced on the face of the stack. Air directed downwardly upon a stack permeates the porous pieces so thoroughly that the top piece cannot be floated or otherwise separated. Air directed into edges of the stack fails utterly to solve the problem.

However, as we have disclosed in an earlier patent application, a top piece can be loosened by the use of a stream of air over the upper surface of a cloth in which high speed portions rushing over the upper surface produce both lift and flutter, and boundary portions of the stream, which move slower, pass through the cloth, the eflects combining to loosen the piece from the next one.

Further, we taught that the air stream can be made to entrain and separate the margin of the piece following which the piece can be peeled from the stack. But in some instances to attain necessary production speeds while entraining the margin of the piece, compressed air is required, that is to say, air from a pressure source of 5 psi. or above, which requires a heavy air compressor and other expensive equipment.

The principal object of this invention is therefore to provide efficient, economical and reliable means for separating a top piece of fabric from a stack.

Other objects are to provide means for loosening a top piece instantaneously over a substantial area; to decrease frictional engagement of a top piece with the adjacent piece and enable it to be dragged over the stack; to provide means for exerting an inward pull on a top piece to move it towards its center; to provide means for accomplishing all of the above using blower air, that is to say, a stream of essentially uncompressed air which has a total pressure substantially less than 5 p.s.i. and is characteristically produced by low cost rotary equipment such as the common household vacuum sweeper; to provide means for rapidly dragging a top piece from a stack and delivering it to a conveyor; and to provide machine designs which can be employed for a wide range of fabrics.

According to our invention, a top piece of fabric can be loosened over a wide area without disturbing the stack by applying a lift to a small part of the piece and 3,1583%? Patented Feb. 2, 1965 causing a stream of relatively high static-pressure air which may be produced by a blower to move through some of the lifted part without flattening it against the stack.

Preferably, we produce the lift on the piece by means of a zone of low static pressure acting on a small portion of the upper surface, and we produce a zone of relative high static pressure blower air upon a small, contiguous portion of the surface with the lifting effect of the flow pressure zone exceeding the flattening effect of the higher pressure zone so that the portion exposed to the higher pressure air is raised and air flows through it. The slight air pressure that is created beneath the porous piece is sufficient to prevent the raising of the second piece and to cause portions of the top piece to flex upwardly. The upward forces acting on the piece. exert lateral, inward tension on it. The result is a general decrease, although not elimination, of the frictional contact between the top piece and the stack.

Further, we have discovered that a single flow from a blower in combination with a battle surface can simultaneously produce the low pressure lift and the higher pressure zone. In one preferred embodiment this takes the form of a blower nozzle directed downwardly, preferably vertically, against the top piece, and an impermeable baflie plate extending outwardly from the nozzle parallel to the piece, the plate being raised above the stack to allow distortion of the top piece. Some of the air rushes outwardly under the baffie, producing the low pressure zone while air that is trapped has its velocity head converted to a static head, and produces a slow speed flow through the fabric as desired.

In another embodiment a curved baffle having a thin upturned margin receives an air stream on its upper surface, directed towards the margin. The exposed side of the margin deflects the air upwardly, which produces a low pressure zone on the other side of the margin toward which a part of the piece of fabric is raised. A small opening in the margin allows some of the air stream to press against the raised part without flattening it, which produces a relatively low speed flow through the piece.

We have further found that the top piece of fabric, when loosened by the air, can be dragged without distrupting the alignment of the remaining pieces, and we have found particularly efficient and reliable snagging means for engaging the pieces to lift and drag them.

All of the above will be explained more fully in connection with the accompanying drawings, wherein:

FIG. 1 is a cross-sectional diagrammatic view of a preferred embodiment of the invention;

FIG. 2a is a perspective view of an embodiment employing an annular baffle plate;

FIG. 2b is a perpective view of an embodiment employing a rectangular baffle plate;

FIG. 2c is a perspective view of an embodiment employing the bafrle of FIG. 2b and impermeable flexible sheet extensions;

FIGS. 3a and 3b are side and plan views, respectively, of another embodiment employing a curved baffle;

FIG. 30 is a perspective View of an embodiment similar to that of FIGS. 3a and b, but formed to have a loosening effect radially in all directions;

FIGS. 4 and 5 are side and plan views, respectively, of a preferred embodiment of a machine employing the baffle plate of FIG. 21;;

FIGS. 6 and 7 are views of the snagging device of the machine taken along lines 6-6 of FIG. 4 and 7-7 of FIG. 5, respectively;

FIG. 8 is a view similar to FIG. 7 showing the snagging device following its rotation by an increment;

IFIGS. 9 and 10 are side and plan views, respectively, of another embodiment of a snagging device.

Referring to FIG. 1, a 1 /2 horsepower vacuum sweeper blower .12 capable of producing 1 /2'p.s.i. static air pressure when blanked-off is connected to a vertical duct 14 which in turn is connectedto' cylindrical nozzle 16 vertically slidably mounted on duct 14. A horizontal baffle plate 20 surrounds the nozzle to which it is secured. Beneath the nozzle and plate a platform 21 holds a stack of fabric pieces 22, including top piece 22". In this embodimentthe nozzle 16 has a diameter of 1% inches, slightly less than the outlet from the blower, and,

the fabric pieces are 18 inches long,.dimension L in FIG. 1.

The blower air is introduced downwardly as shown by arrow 26. The portion A of the :top piece 22 in direct alignment with snow 26 is indented by the force of the air anda cone 27 of essentially still entrapped air is formed.

When a fabric piece is first exposed to the baffle plate, for instance, as soon as the piece above it has been removed, a number of things take place virtually instantaneously. First, a small passage tends to form between the bafile plate 20 and thefabric piece 22' under the influence of the air pressure. Second, the air rushes lateral ly through the narrow passage in high speed stream 28, creating a zone of low static pressure which starts to raise part B of the piece. Third, since the flow cross-section for the high speed air 28 increases outwardly from the center of the air tube and air leaks upwardly from beneath the top piece, the high speed air slows'and decays,

its velocity head partially converting to static pressure head, and applies a slight upward force on the outer part 2000f the plate which tends to hold it away from the stack. Fourth, the middle portion C of the fabric which is contiguous to the portion B, is formed into an upstanding wall in the space between the stack and the a plate. This occurs only in the top piece because air stream tional engagement between the top piece 22 and the stack 22 is reduced. Sixth, as the'high speed air stream decays at 29,..it produces turbulence. This applies high frequency compressions and rarifactions to the face of the piece causing it to flutter at 31, the waves 33 propagating outwardly, loosening the piece and reducing frictional engagement. Seventh, the forces which produce the raised wall C and the forces which form the extensive air pocket 39 exert inward tension on outlying portions of the piece which move inwardly despite the air 28 rushing in the opposite direction. This movement adds to the portion of fabric which forms the wall C. If the fabric is not elastic, the edges of the'piece can even move inwardly.

In the foregoing embodiment the distance H between the plate and the stack is adjustable by the action of the air flow, the bafiie plate 26 andplatforrn 21 being biased together by the free weight of the nozzle and plate with a force of about 1 pound which is less force than that produced by the air. By this arrangement, before the air flow begins the plate can rest on the stack and when op erating, the plate is raised about /2 inch above'the stack. The provision of automatic 'adjustability enables the device to automatically compensate for variations in air flow. Whether this or some other means for positioning the plate is employed, a limitation to be observed to obtain a useful effect is that the baffie plate must not be forced down to flatten the top piece, but rather, in operation it must be spaced above the stack because the fabric wall C must have room to form.

It is most advantageous to have a substantial flow of air. As an example, We found that a single 1 /2 inch diameter nozzle receiving thewhole output of an ordinary household vacuum sweeper loosens 14x 30 inch towels effectively.

Furthermore, we have found that if the pressure of the air is much increased over that produced by the'household vacuum sweeper, a number of detrimental effects occur: the increased static pressure of the entrapped air tends to flatten the wall of fabric; the pile is deeply indented underthe air tube, increasing frictional engagement there between the top piece and the next adjacent piece; and

high loss of'the relatively expensive air occurs if the baffie plate is not pressed tightly against the stack, but such pressing further forces the piece against the stack to defeat the desired action. Whether or not a given air pressure will give some beneficial effect depends-on many things, such as the type of fabric and the particular geometry of the elements selected. We believe for the embodiment of FIG. ,1,- the air pressure should be lessthan 5 p.s.i. The lighter and more porous the material, the less air pressure is required.

With the air sources we have most successfully employed, producing about 1- /2 p.s.i. static pressure at blankoff, we have found the spacing H of the bafiie surface above the stack, and the corresponding height of the wall C of fabric, should be about A, of the diameter of the air supply nozzle and'preferably on the order of to /2 inch. The bafilev surface need not extend very far outwardly from the nozzle. The further it extends, the more resistance it produces to the flow of the highspeed air, which decreases the lifting effect. With the arrangement described above, we have found that optimum results occur with a baffle plate extending outwardly of the nozzle on the order of less than /2 to 3 times the diameter of the nozzle, and preferably no more than about 4 inches when the'preferredhousehold vacuum sweeper air supply is employed.

The angle of'the downward blast to the surface of the piece should not be less than about 30, depending to some extent on the surface finish of the fabric piece. Smaller angles apply such high outward forces onthe piece that it cannot pull inwardly to allow growth of theupstanding wall C. To obtain a loosening effect in all directions, the nozzle should discharge substantially vertically and the baifle plate should-surround the nozzle.

Referring to FIG. 2a, the air supply duct 16' is vertical and the baffle is an annular plate 20 extending horizontally beyond the nozzle inevery-direction for a distance slightlyless than the diameter of the nozzle. This plate works well upon pieces which are about as long as they are wide, the loosening effect extending radially about 10 inches. The high speed air flow provides a uniform ring of lifting forces'on the face of the fabric, the higher static pressure zone of entrapped air lies within this ring, and

. the-Wall of fabric takes the form of a crater.

. about 3 inches x 8 inches andthe nozzle 1 /2 inches in In operation, the long dimension of the plateis disposed transversely to the length of elongated pieces, over the center of the stack. Since the flow paths for the diameter.

high speed air are shortest in the direction of the middle of V the longer edges, more air rushes through these paths than elsewhere; The raising effect on the fabric is greatest at these paths so high walls can here be formed and the air pocket can be greatest in these directions. Furthermore,-

since the high speed air stream is'strongest in these directions, it hasa greater turbulent effect as it decays, which forms strong flutter waves which can propagate to the remote edges of the fabric piece. The long ends of the plate provide ample piston area for raising the plate sufficiently to allow distortion of the fabric.

Referring to FIG. 2c, the same plate of FIG. 2b is employed, with thin, flexible, impermeable and slick extensions 21, e.g. of plastic sheeting, secured to its long edges. These extensions confine the high speed air against the face of the pieces, so that the fluttering effect is maximized while they offer little resistance to the air flow. In some instances these extensions improve the loosening effect and allow a single size and relationship of the components to perform over a wide range of operating conditions.

Referring to FIGS. 3a and 3b, a baffle member has a surface portion extending generally parallel to the top of stack 54, and a thin margin portion 56 turned upwardly. A blower air supply nozzle 58 is disposed to discharge at 60 over the top surface of the bafiie. This air is deflected by margin 56 and moves upwardly in the direction of arrow 62. This creates a low pressure zone 64 on the opposite (convex) side of the margin 56 and a small portion 66 of the piece of fabric is raised towards this zone. A small, longitudinal slot 68 is cut in the margin 56. The portion of the air stream in line with-slot 68 moves in the direction of arrow 69 through slot 68 and through the portion of the fabric exposed by the slot, the air slowing and its static pressure increased by the resistance it encounters. The slot is sufiiciently narrow, e.g. inch, so that the force of this air does not flatten the raised portion back against the stack. The air passes through the fabric and it forms a slightly pressurized zone 70 which loosens the top piece in the manner described above.

Referring .to FIG. 30, the same general form of structure is employed as in FIGS. 3b and b, except that the margin 56 of the home is a surface of revolution and the air moves radially in every direction to lift the fabric to form a raised fabric ring and a multiplicity of radial slots 68' are employed.

Referring to FIGS. 4 and 5, there is shown a machine for rapidly removing double layer knit-ted pieces from a stack in the making of baby clothes and delivering them to a conveyor. 7

The machine comprises a platform for supporting a stack of the pieces 82, the platform having a supporting leg 84 slidable upon frame 86. A spring loaded pusher 87 supports the stack and biases it upwardly with about 1 pound excess force. Above the stack is a vertical air nozzle 88 fixed to the end of blower tube 90 and a surrounding .bafie plate 92 fixed to the nozzle. The diameters of the nozzle 88 and tube 90 are about 1% inches. The tube 90 is connected to the discharge side of a l horsepower dust collector 96, which has a blankoff discharge pressure of 2 psi. gauge.

At the forward end of the stack, there is a rotary dragging member 98 disposed about /2 inch above the marginof the top piece. Preferably, as shown, this member is supported within a roll 99 which forms a nip with conveyer belt 100 at a point spaced from the stack. Transfer belts 102 extend about the portion of the roll that faces the stack, and leave the roll after the nip with the conveyer belt, traveling above the conveyer to idler roll 104, then back to the periphery of roll 99. The pick-up member 98 operates with light vacuum, and to this end, a vacuum duct 106 is connected to the intake side of the dust collector 96. The double layer pieces have their folded edges 93 on the side of the stack opposite from the pick-up member. When the working part of the pick-up member 98 passes over the margin 85 of the top piece, it can be snagged by the pick-up member and removed in a manner new to be described.

Referring to FIGS. 68, the snag pick-up member is rotatable and comprises a series of vacuum holes connected .to the light vacuum duct 106, disposed to draw the margin 85 of the piece upwardly when the holes are directly thereabove. A horizontally disposed knife 114 is 6 positioned rearwardly of the holes 115 and closer to the stack than the holes extending crosswise of the stack with its edge disposed outwardly in the direction of movement. An abrasive coating 116 is preferably provided on the knife edge. When the light vacuum attracts the margin 85 of a piece, the margin is drawn across the edge of the knife. The margin is distorted about the edge providing what we term a snagged engagement. The preferred abrasive surface increases the strength of this engagement. When the knife edge is moved outwardly to overcome the frictional restraint between the top piece and the stack, the restraint acts to pull the margin even tighter about the knife edge, making the engagement even more secure.

Referring to FIGS. 4, 5 and 8 in operation, the air blowing through the loosening device 88, 90, 92 decreases the frictional engagement between the top layer and the second one, the pick-up member 98 engages the margin 85 and drags the top layer over the stack, and the next layer peels at 93 from the stack. Even if initially the margin of the second layer be raised with the margin 85 of the first when the vacuum is applied through openings 115, the frictional engagement between the second layer and the third prevents the second layer from being dragged with the first.

After the margin 85 of the top layer passes through the nip between conveyer 100 and roll 99, the belts 102 press the piece outwardly from the knife edge, the piece, readily detaches and is deposited progressively on the conveyer.

The machine has the same operation with single layer pieces except there is no peeling action.

By picking up each piece at its margin and employing a dragging motion, every part of the first piece must pass over the edge of the stack before the next one is exposed to the pick-up member. Therefore, should the pick-up member fail to carry one piece all the way off, no harm is done, for on return it will grasp only the missed piece and remove it. Such removal machines are capable of handling as many as 8000 :pieces per hour, and can even handle wet and unevenly stacked pieces.

The vacuum supplies a force for raising the top piece into engagement with the snagging member, but not for dragging it as this is performed by the snagging means.

Accordingly, the vacuum can be very light which presents little danger that the second layer will even be initially disturbed.

While the foregoing snagging means is preferred, some variations are suitable for certain materials. For a high friction cloth, the abrasive coating need not be employed while for relatively stiff cloth and even for towels, the abrasive surface alone is sufiicient because it has a snagging effect upon the individual threads of the fabric. The abrasive surface can take various forms, e.g. sandpaper, hack-saw blades or ,an outwardly punched metal plate. The abrasive surface and a vacuum opening can extend in the direction of movement of the pick-up member rather than in the transverse direction.

Referring to FIG. 9, another snagging device which does not even require vacuum but operates satisfactorily on thick materials is shown. It comprises a series of straight pins 120 secured to the top surface of a thin, flexible and resilient metal sheet 122, the pins extending outwardly from the sheet about Ms inch in the direction of movement of the fabric. The plate is'mounted on a movable support which is caused to oscillate. Upon initial contact the plate lies at an angle a to the top piece on the order of about 20. After the edge of the plate contacts the piece, it slides rearwardly as the plate is caused progressively to press down face to face on the top piece, pin end first, with an arcuate movement of the plate and its support arm 125 about a center 123 located vertically below the forward edge of the stack. Then the plate is allowed to raise in the reverse arcuate movement, with the rearward portion of the plate coming r up first so that the pins turn about their points. These serving alone to differentiate the vpiece from the stack.

With further movement of the deviceand because of decrease in friction due :to the air loosening device 150 as describedabove, the piece is dragged over the face of the stack. 7

The foregoingembodiments'ihave been presented to illustrate the invention. Since fabrics vary in characteristics, changes in the specific details may be required. As examples, the cross-sectional shape of the airsupply tube can be of various configurations; for use on elongated. pieces like trousers legs, two or more of the loosen- -ers, spaced considerably apart so they will notconfiict or disruptthe effect of each other, can be employed; the pinlifter or the knife edgeorth'e abrasive device can be employed to raise a central portion of the fabric and air can be directed against the raised portion to forman air zone between the top piece andthe stack and to cause flutter in the top piece. Theseand other changes in the specific details of the invention-can be made within its spirit. and scope.

What is claimed is:

1. A cloth loosening apparatus for loosening the top sheet of cloth from a stack by distorting said sheet, said apparatus comprising a wall forming means located inwardly from the edges of said top sheet, said wall forming means arranged to apply a lifting :force to a predetermined part of said sheet to form a wall therein, said wall forming means providing an open space above said.

stack in which .said wall can stand at a substantial angle to an adjacent part. of said sheet, said wall forming means adapted toform said wall without pressing said adjacent part against saidstack, and positive pressurized air-means including means supplying air under positive pressure arranged to produce a lateral stream of such air against the outer surface of said wall, in the general direction of said adjacent part of said sheet, whereby said air stream can at least partially pass laterally through said wall, thence laterally between said adjacent part andsaidstack to loosen said adjacent part from said stack.

2. The apparatus of claim 1 in combination with a removal means adapted to engage a margin of the top sheet that is under the influence of said loosening apparatus, said removal means adapted to remove said margin from said stack without removing a second sheet, said removal means comprising a movable cloth engaging member having a gripping point about which said cloth can distort and a vacuum source of predetermined slight degree associated with said point arranged to draw said cloth to and distort it about said point, and means adapted to move said point upwardly from said stack in a removing action.

3. A cloth loosening apparatus for loosening the top.

sheet of cloth from a stack by distorting said sheet, said apparatus comprising a wall forming means located inwardly from the edges of said top sheet, said wall forming means arranged to apply a lifting force to a predetermined part of said sheet to form a wall therein, said wall forming means providing an open space above said stack in which said wall can stand at a substantial angle to an adjacent part of said sheet, saidwall forming means adapted. to form said wall without pressing said adjacent part against said stack, said wall forming means compris ing means defining an airbafiie surface and positive pressurized airmeansincludingmeans supplying air under positive pressure, said positive pressurized air means arranged to direct a streamof air through an outlet against a predetermined localized area of said top sheet of cloth on said stack, said outlet having a substantial flow crosssection sufiicient to cause said air stream to substantially indentsaid localized area of said top sheet into said stack, whereby a body of air can'be entrapped at the outer surface of said sheet in said indentation, said air means located so that an extendedarea. of said sheet that is free of such indentation by said positive pressurized air means is located adjacent said localized area, said battle surface extending from said localized area in the direction of said extended area, said baffie surface and said outlet cooperatively arranged and positioned .to enable air to flow adjacent to said baflle surface and lift the corresponding part of said cloth, said bafile surface arranged to be-spaced apart from said stack to provide said open space above said stack whereby said air flowing adjacent said baffie surface can lift part of said cloth unimpededly into a wall standing at a substantial angle .to said extended area of said sheet, and said voutlet and bathe surface cooperatively arranged to enable pressurized air to move from said localized area laterally against the outer surface of said wall, in the general direction of said extended area of said sheet, whereby said pressurized air can at least partially pass .laterally through said wall, thence laterally between said extended area of said sheet and said'stack to loosen said extended area from said stack.

4. The apparatus of claim 3 wherein said means defining said airbatlie surface comprises an extended piston plate under which flows air from said outlet, said plate mounted for movement away from the face of said stack, the lateral extent 'of said plate cooperatingly arranged with the flow characteristics of said outlet to insure that the air is in the turbulent state before escaping from under said plate, said plate arranged tornove outwardly from said stack in response to and in an amount dependent upon the force exerted thereupon by said air, whereby because the height of said wall as 'well as said force is dependent upon the amount and pressure of said air, said apparatus is self-regulating to provide space for said wall to form.

-5. The apparatus of claim 3 wherein said means supplying air under positive pressure comprises a rotary air blower, said fiow cross-section of said outlet being in excess of one square inch, said battle surface including an imperforate baffle plate that surrounds said outlet for said air stream, said plate extending laterally therefrom in every direction.

6. The apparatus of claim 3 wherein the portion of said baiile surface immediately adjacent said outlet is a plate member under which flows air from said outlet, and'an outer extension of said bafl'le surface comprises a thin flexible sheet member secured to said plate member adapted to flex with change in the volume and pressure of the air thereunder while enhancing the loosening effect of turbulent air flowing over the outer surface of said top sheet on said stack.

7. The apparatus of claim 5 adapted toloosen an elongated cloth piece wherein said baffle plate extends from each side of the outlet in the direction of the length of said piece a distance no greater than about the diameter of the outlet, and is substantially narrower in that direction than in the direction of the width of said piece.

8. A cloth loosening apparatus for loosening the top sheet of cloth from a stack by distorting saidsheet, said apparatus comprising a wall forming means arranged to apply a lifting force to a predetermined part of said sheet to form a-wall therein, said wall forming means providing an open space in which said wall can stand at a substantial angle to the top of said stack, said wall forming means comprising an air baffie surface and positive pressurized air means including means supplying air under positive pressure, said'means defining said air baflle surface including a member positionable over said top sheet having an upwardly directed air deflecting bafiie surface, said member having a margin turned upwardly relative to said top sheet, said positive pressurized air means arranged to produce a stream of air flowing laterally over said upwardly directed bafile surface toward said upwardly turned margin, said margin adapted to deflect upwardly a major portion of air flowing thereagainst and thereby create a low pressure zone on the opposite, underside of said upwardly turned margin toward which a part of said sheet can rise into a wall, an air passage at said battle surface, below the top part of said margin, arranged to enable a lateral stream of air from said positive pressurized air means to flow past said bathe surface and against the outer surface of said raised Wall, whereby said lateral air stream can pass laterally through said wall, thus loosening said sheet from said stack, said bailie surface and said positive pressurized air means cooperatively arranged and positioned so that the size of the lateral stream of air flowing against the outer surface of said Wall is sutiiciently sznall so that the force of said air does not overcome the raising force produced by said low pressure zone.

9. The apparatus of claim 8 wherein said air passage at said bafiie surface which enables air to flow past said baffle surface and against said Wall is defined by a slot formed in said bafile surface, said batile surface extending to each side of said slot.

10. A cloth loosening method for loosening the top sheet of porous cloth from a stack of porous cloth sheets by distorting said sheet, said method comprising, applying a lifting force to a predetermined part of said sheet at a position located subtantially inwardly from at least one edge thereof to form a wall therein While providing an open space above said stack in which said wall can stand at a substantial angle to an adjacent part of said sheet, applying said lifting force to said predetermined part in such a manner as to cause said Wall to stand in said space at a substantial angle to an adjacent part of said sheet so that said sheet in said region is distorted from a flat condition to an upwardly bent condition, applying said lilting force without pressing said adjacent part of said sheet against said stack, by means of positive pressurized air means, producing a lateral stream of air against the outer surface of said Wall in the general direction of said adjacent part of said sheet, thereby causing said air stream to at least partially pass laterally through said wall, thence laterally between said adjacent part and said stack to loosen said adjacent part from said stack.

11. A method of loosening a piece of cloth from a stack comprising lifting a small portion thereof at a position located substantially inwardly from at least one edge thereof and passing air under positive pressure through said lifted portion and thence between said piece of cloth and the stack to decrease the frictional engagement between said top piece and the next adjacent piece and to apply inward tension to a portion of said top piece sufficient to pull an edge thereof inwardly, and simultaneously passing turbulent air over the face of said top piece causing flutter therein, applying this turbulent air stream in a manner to avoid overcoming the inward tension in said top piece.

References Cited in the file of this patent UNITED STATES PATENTS 685,370 Bridgewater Oct. 29, 1901 1,155,503 Moore Oct. 5, 1915 2,466,766 Harrold Sept. 3, 1946 2,576,636 Opgenorth Nov. 27, 1951 2,819,075 Noon Jan. 7, 1958 2,319,076 Vt/endt et al. Ian. '7, 1958 2,953,371 Smith Sept. 20, 1960 

1. A CLOTH LOOSENING APPARATUS FOR LOOSENING THE TOP SHEET OF CLOTH FROM A STACK BY DISTORTING SAID SHEET, SAID APPARATUS COMPRISING A WALL FORMING MEANS LOCATED INWARDLY FROM THE EDGES OF SAID TOP SHEET, SAID WALL FORMING MEANS ARRANGED TO APPLY A LIFTING FORCE TO A PREDETERMINED PART OF SAID SHEET TO FORM A WALL THEREIN, SAID WALL FORMING MEANS PROVIDING AN OPEN SPACE ABOVE SAID STACK IN WHICH SAID WALL CAN STAND AT A SUBSTANTIAL ANGLE TO AN ADJACENT PART OF SAID SHEET, SAID WALL FORMING MEANS ADAPTED TO FORM SAID WALL WITHOUT PRESSING SAID ADJACENT PART AGAINST SAID STACK, AND POSITIVE PRESSURIZED AIR MEANS INCLUDING MEANS SUPPLYING AIR UNDER POSITIVE PRESSURE ARRANGED TO PRODUCE A LATERAL STREAM OF SUCH AIR AGAINST THE OUTER SURFACE OF SAID WALL, IN THE GENERAL DIRECTION OF SAID ADJACENT PART OF SAID SHEET, WHEREBY SAID AIR STREAM CAN AT LEAST PARTIALLY PASS LATERALLY THROUGH SAID WALL, THENCE LATERALLY BETWEEN SAID ADJACENT PART AND SAID STACK TO LOOSEN SAID ADJACENT PART FROM SAID STACK. 